1. Field of the Invention
The present invention relates to an image forming system for performing image formation on both surfaces of a recording sheet.
2. Description of the Related Art
In a conventional image forming system, as disclosed in Japanese Patent Application Laid-Open No. 2004-268572, a first image forming apparatus for performing image formation on a front surface of a recording sheet and a second image forming apparatus for performing image formation on a back surface of the recording sheet are connected to each other to perform the image formation on both the surfaces of the recording sheet.
The recording sheet on the front surface of which an image has been formed by the first image forming apparatus is transported to the second image forming apparatus with the front surface and the back surface being reversed. Then, the second image forming apparatus performs the image formation on the back surface of the recording sheet.
Japanese Patent Application Laid-Open No. H11-212424 discloses an image forming apparatus capable of adjusting a position of an image formed on a recording sheet by forming a pattern image for image position adjustment on the recording sheet and allowing a user thereof to examine the formed pattern image and input an adjustment value of the image position through an operation unit. In the image forming apparatus, a timing at which registration rollers perform image registration is adjusted based on the adjustment value of the image position input by the user.
In a case where the image position adjustment disclosed in Japanese Patent Application Laid-Open No. H11-212424 is performed in the image forming system disclosed in Japanese Patent Application Laid-Open No. 2004-268572, the first image forming apparatus forms the pattern image for the image position adjustment on the front surface of the recording sheet, and the second image forming apparatus forms the pattern image on the back surface of the recording sheet.
In this case, the pattern images are formed respectively on the front surface and the back surface of the recording sheet. Therefore, the user finds it difficult to input such an adjustment value that is appropriate to bring the image formation positions for the image forming apparatuses to coincide with each other. There is another problem that the user needs to examine both the pattern images on the front surface and the back surface of the recording sheet, which takes time and labor.